A. Field of the Invention
The present invention relates to an automatic analysis apparatus and an automatic analysis method for analyzing items contained in a mixed solution and more particularly, to an automatic analysis apparatus including a plurality of light sources for automatically analyzing multiple items contained in a mixed solution, such as human fluids with high precision by exchanging the plurality of light sources in accordance with designated analyzing items.
B. Background of the Invention
An automatic analysis apparatus mainly measures biochemical examination items contained in fluids such as blood or urine. Generally, an automatic analysis apparatus for performing biochemical tests employs spectrophotometry in order to analyze a particular item by dispensing a prescribed amount of an object sample and a prescribed amount of reagent corresponding to the item into a reaction cuvette. In the cuvette, the dispensed object sample and the corresponded reagent are mixed and stirred so as to react at a prescribed temperature. Spectrophotometry measures a density or an activity of an object measuring substance or an enzyme contained in the object sample based on a change of color tone due to light absorption of the mixed solution.
In the spectrophotometric biochemical test, a mixed solution of an object sample and a reagent dispensed in a reaction cuvette is irradiated by a light from a light source. A light detector in the spectroscopic analyzer uses a transmission light to detect a change of color tone of the solution due to reaction of the object sample and the reagent. Thus, an item to be measured is detected based on a change of a particular wavelength component absorbed in the reacted solution.
Besides the biochemical test, an immune serum test is also used for analyzing fluids. The immune serum test employs turbidimetric immunoassay in order to acquire an item density of an object sample by measuring a turbidity change of the object sample due to an agglutination of the mixed solution that is generated by scattering lights which is due to a reaction between an antigen and an antibody in the solution of the object sample.
Besides the turbidimetric immunoassay, a latex agglutination turbidimetric immunoassay is also employed to measure a turbidity change of the object sample due to agglutination that is caused by a reaction between an antigen in an object sample and an antibody sensitized latex that is sensitized latex particles. In either of the turbidimetric immunoassay, a reagent is adjusted for the applicable measurements to be performed in each particular immune serum test apparatus. Consequently, possible items to be measured also are limited by each particular immune serum test apparatus.
Recently, an increase in efficiency and a reduction of a cost of the biochemical test and the immune serum test are keenly required. To meet this demand, a single analyzing apparatus that can be used to perform a plurality of measurements for a plurality of test items including both the biochemical test and the immune serum test in a single analyzing apparatus is required. Particularly, since automatic analysis apparatus for biochemical tests can be used to perform high speed processing for many tests of a plurality items to be measured, it is possible to use an automatic analysis apparatus for immune serum testing.
As explained above, spectrophotometry is typically employed for an automatic analysis apparatus in which an optical system measures a change of color tone of a solution in a cuvette by detecting a light transmitted through the cuvette. The change of color tone of the solution is generated by the light absorption of the solution due to reaction between an object sample and a reagent. Thus, the conventional automatic analysis apparatus does not take any measurement of a light source for performing an immune serum test in which a measurement of the particular amount of transmitted light is necessary to perform a turbidimetric immunoassay in order to measure a change of turbidity of a sample solution due to the scattered transmission light caused by agglutination of the solution. Consequently, even if an optical system itself in the conventional analysis apparatus of biochemical tests is used for measuring a turbidity change of a transmitted light to perform an immune serum test, the transmitted light is reduced lower than a necessary amount because of the scattering of light due to agglutination of a solution. Such lowered amount of light generates a lower accuracy of a measurement.
Japanese patent application publication 2001-141654 proposed a spectrum luminous intensity/turbidity detection unit that is combined both of a penetration light measuring optical unit and a scattered lights measuring optical unit for applying to an automatic analysis apparatus. However, the proposed spectrum luminous intensity/turbidity detection unit needs to separately provide both a transmitted light detection unit for measuring a change of color tone and a transmitted light detection unit for measuring a change of turbidity. Thus, the proposed automatic analysis apparatus simply combines both a transmitted light detection unit for spectrophotometry and a transmitted light detection unit for a turbidimetric immunoassay. Consequently, the proposed apparatus including both spectrophotometry and turbidimetric immunoassay functions has serious problems for constructing a complicated optical system including light sources and transmitted light detection units. Further, the proposed apparatus is inevitable larger.